(1) Field of the Invention
The present disclosure relates to a display device, and more specifically to a liquid crystal display device in a lateral electric field mode excellent in viewing angle characteristics.
(2) Description of the Related Art
In the liquid crystal display device, a TFT substrate includes a pixel having a pixel electrode, a thin film transistor (a TFT), and the like formed in a matrix configuration, a counter substrate is disposed opposite to the TFT substrate, and a liquid crystal is sandwiched between the TFT substrate and the counter substrate. An image is formed by controlling the optical transmittance of liquid crystal molecules for individual pixels. Since the liquid crystal display device is flat and light-weight, the use is widely spread in various fields. Small-sized liquid crystal display devices are widely used in a mobile telephone, a DSC (Digital Still Camera), and the like.
In the liquid crystal display device, a problem is viewing angle characteristics. An IPS (In Plane Switching) mode is a mode in which liquid crystal molecules are rotated in a direction in parallel with the main surface of a TFT substrate, and viewing angle characteristics are excellent more than in other modes. However, also in the IPS mode, a difference is taken place in the viewing angle characteristics in the azimuth angle direction related to the rotation direction of the liquid crystal molecules.
Japanese Unexamined Patent Application Publication No. 2005-196118 describes a technique in which comb tooth electrodes directed in various directions are formed in a single pixel for aiming to decrease azimuth angle anisotropy. Japanese Unexamined Patent Application Publication No. 2009-237541 describes a technique in which a comb tooth electrode is bent in a single pixel, and the rotation directions of the liquid crystal molecules are varied for aiming to uniformize the viewing angle characteristics. Japanese Unexamined Patent Application Publication No. 2012-53137 describes a technique in which the directions of the slopes of pixel electrodes between pixels adjacent in the vertical direction are in opposite directions for aiming to uniformize the viewing angle characteristics for every two pixels.